Linux Mint's purpose is to produce an elegant, up to date and comfortable GNU/Linux desktop distribution. It was now originally based on Ubuntu but is now more of a Debian derivative in its own right. This gives it a stable base and access to a large amount of software, from its own collection and those of Ubuntu and Debian.
Ease of use is one of its main features and it is one of the few Linux distributions to handle all common media types "out of the box". Most distributions produce a single, worldwide version, so they have to leave out media codec that may not be allowed in some countries. Linux Mint produce two versions, one satisfying the need to only include open and free software and the other including all the media codecs you could need. The latter is the default download.
Linux Mint is a community supported distribution and the developers are very active on their forums, often implementing features as a direct result of a request from users. This results in a rapid release cycle, although there is also paid support and longer term releases for those that wish to use Mint in a commercial environment. The default desktop environment is GNOME, but there is also a KDE version and one using the lighter (and faster) XFCE desktop. 32 bit and 64 bit versions are provided, so you have plenty of choice.
Note that this is the 15th release of Linux Mint.